The Harrier Jump Jet is the worlds only vertical take
off and landing jet fighter. It was developed by the British in an era
of financial cutbacks which saw the end of the large Royal Navy Aircraft
Carriers. It can use airfields on land or fly from smaller aircraft
carriers at sea and is flown by the best US and British pilots. It
combines the best aspects of a helicopter with those of a fighter jet.
For example, the world speed record for a helicopter is 249 mph (Linx
helicopter) whilst the Harrier can fly at 730 mph.

The Harriers most famous feature is its vertical take
off and landing capability. Although the Harrier has one jet engine (The
Pegasus) it
has four nozzles that direct the jet engine thrust downwards for
vertical lift. (Diagram 1)

Once airborne the nozzles are slowly revolved so that
the plane moves forward. (Diagram 2)

Vertical take off and landing uses an enormous amount
of skill on the part of the pilot and also a large amount of fuel. The
Harrier can only hover for 90 seconds, in this time it uses 150 gallons
of water to keep the engine cool.

To save fuel a simple ramp allows the plane to take
off on a very short runway. This is used by the Royal Navy Carriers. The
planes appear to hop into the air.

Vents at the ends of each wing can be used to direct
some of the thrust and this allows the pilot to move the plane left,
right, forwards and backwards - whilst hovering.